Electric circuit breaker



April/22, 1947- c. H. FLURscHElM 2,419,446

I ELECTRIC CIRCUIT BREAKER Filed July 18, 1944- 5 Sheets-Sheet 1'Inventor: Cedric Harold Flurschem,

b 1M MMA, y His Attorney.

April 22, 1947. c. H. FLURscHElM 2,419,446

ELECTRIC CIRCUIT BEAKER Filed July 18, 1944 5 Sheets-Sheet 2 inventor zCech"c Harold Flurscheim,

His Attorney.

April 22, 1947. c. H. FLURscHElM 2,419,446

ELECTRIC C1RCUIT BBEAKER Filed July 1:2, 1944 5 Sheets-Sheet 5Invervtcpr* Cedric Harold Flurschem,

l/MQVMJ im O t www w April 22, 1947- c. H. FLURSCHEIM 2,419,446

ELECTRIC CIRCUIT BBEAKER Filed July 1s, 1944 5 sheets-sheet 4 InVeni-,o1` lCedric: Harold Flurschem,

by f JM HIS Attorney.

April 22, 1947. c. H. FLURSCHEIM 2,419,446

ELECTRIC CIRCUIT BREAKER Filed July 18, 1944 5 Sheets-Sheet 5 PatentedApr. 22, 1947 UNITED STATES ELECTRIC CIRCUIT BREAKER Cedric HaroldFlurscheim, Bowdon, England, assignor to Metropolitan-Vickers ElectricalCompany Limited, a British company Application July 18, 1944, Serial No.545,440 In Great Britain July 28, 1943 9 Claims.

This invention relates to air or gas blast electric switches or circuitbreakers of the kind in which cooperating contacts mounted within acontact or arcing chamber are adapted to be separated by the applicationof pressure to said 5 chamber which is provided with one or moredischarge openings or the equivalent so that said pressure will cause ablast of air or gas past the contacts thereby to extinguish the arcdrawn upon interruption of the circuit through said contacts.

In a well-known form of such switches the arcu ing or contact chamberabove referred to comprises a tubular member of insulating materialWithin which the contacts are mounted for relative movement parallelwith the axis of said tubular member, the air or gas for producing theblast being caused to flow axially through said tubular member and pasta nozzle therein which may be formed by one of the contacts or by aseparate member such as of insulating material. Such arrangements,however, suffer from the dis advantage that the contacts andparticularly the moving contact displaceable by the pressure within thearcing chamber are not readily accessible.

The present invention has for its object to provide an improvedarrangement of arcing or contact chamber and contacts which Whilstapplicable in a single-break switch is well adapted where desired forapplication in series with one or more similar units to provide amultibreak switch. The invention also provides according to anotheraspect, such arrangements whereby improved accessiblity of the contactsand particularly of a contact or contacts displaceable by `the gaspressure is obtained.

In order that the invention may be more clearly understood referencewill now be made by way of example to the accompanying diagrammaticdrawings, in which Fig. 1 is an elevation mainly in section of apreferred contact arrangement according to the invention,

Figs. 2, 3, 4 and 5 show by way of example several applications of thearrangement according 45 to Fig. 1, Fig. 4 being a plan View of thearrangement shown in Fig. 3,

Fig. 6 shows partly in cross-sectional eleval tion to an enlarged scalean arrangement corresponding with Fig. 5 and incorporating a fur- 50ther feature of the invention,

Fig. "I is an elevation of a further multi-break switch employing aplurality of contact arrangements according to Fig. 1, and

Fig. r8 is an elevationmainlyin cross-section 55 2 showing amodification of the arrangement` of Fig. 1.

Similar parts in the several gures are denoted by like referencenumerals.

Referring iirst to Fig. 1, the contact arrangement is formed as a unitcomprising a fixed main contact I and a co-operating movable contact 2,mounted within a metal Contact chamber 3. The contact I comprises atubular member extending through, and located in a side wall of thechamber 3 by, an insulating bushing 4, which may be of porcelain forexample or may be a condenser type bushing. This bushing is retained inplace by a ring 4a bolted to a flange on a cylindrical portion 5 of thechamber 3. The contact member I is retained in place axially within thebushing by means of a ange Ia and an end plate Ib screwed on to the endof the said member, the ange la and plate Ib abutting against the endsof the bushing 4. The moving contact 2, which is also of the tubularform, extends through a cylinder 6 projecting laterally from the sidewall of the contact chamber 3 opposite to the bushing 4, said movingcontact 2 carrying a piston portion 2a. By means of sliding engagementof the right-hand end of the contact member 2 in a cover plate 'l forthe cylinder 6, the contact 2 is guided for longitudinal movement towardand away from the (zo-operating fixed contact I, the contacts beingshown in the circuit-closed position. The moving contact 2 is connectedelectrically with the cylinder 6 and thereby With the contact chamber asa whole by means of an annular resilient contact construction 8 withwhich the contact has sliding engagement, This resilient contactconstruction may be of any of the well known forms. The contact 2 isbiased into engagement with the contact I by means of a helicalcompression spring 9 surrounding the contact 2 and abutting at its endsrespectively against the contact construction 8 and the pisf ton 2a.

The contact chamber 3 is in the arrangement shown in Fig. l mounted upona tubular insulator pillar, the upper end of which appears at I, and isprovided with a central aperture II in which is registered the upper endof an insulating air supply conduit I2. The conduit I2 is connected atits lower end (not shown) through a suitable control valve with a,reservoir or other source of air (or gas under pressure, the conduitbeing thereby adapted to supply air or gas under pressure to the contactchamber 3 during the circuit-interrupting operation, which air or gaspressure will displace the piston 2a and thereby the moving contact 2toward the right in the drawing so as to separate the contacts. The airor gas pressure within the contact chamber S will then result in flowor" air or gas radially through the gap between the contacts and axiallythrough the passages within the tubular contacts i and E so as toextinguish the arc in well known manner, the air or gas of the blast andthe arc gases being discharged to atmosphere from the outer ends of saidcontacts. if desired suitable means indicated diagrammatically at E3 andI4 may be provided for cooling said gases in otherwise known manner.

The cover plate 'I is secured to a flange l provided on the cylinder' 8by means of bolts lwhereby said cover plate may readily be removed fromthe cylinder so as to allow withdrawal ol the contact construction 8,spring' piston 2a.

and contact 2 from the arcing chamber when inspection of, or attentionto, the contacts is required, this withdrawal of the contact beingfacilitated by the arrangement in which the air supply conduit l2 isdisposed perpendicularly to the direction in which said contact iswithdrawn from the contact chamber. It will be seen that when the partsabove referred to have been withdrawn from the cylinder 5 access mayreadily be obtained through the cylinder E to the contact face o the xedcontact i.

t will be understood that the unit shown in Fig. l may be arranged inany desired manner in a switch or circuit breaker. One example is shownin Fig. 2, this circuit breaker comprising a double-break switchconsisting oi two units A and B each constructed in accordance with Fig.i and mounted on a suitable foundation 23 by means of the tubularinsulating pillars designated il) in Fig. l and designated 3A and ISBrespectively in Fig. 2. The contact chambers 3 of the two units aremounted on the pillars IdA. and I DB so that the two insulating bushingsd extend outwardly away from one another whilst the contact chambers ofthe two units carry fed contacts 22A and 2IB adapted to be connectedtogether by a movable bridging bar 22 which is ixedly mounted at itscentre on a rotatable insulating pillar 23 mounted on the foundation 2Gin a rotatable manner and adapted to be rotated about its vertical axisby suitable operating means as part of the circuit-breaking operation.ln the illustrated position of the bar the latter engages at its twoends with the contacts ZIA and ZIB respectively. rlhe two conductors 33and to be connected by the switch are connected with the end plates Ibof the units A and B, respectively, so that the circuit will proceed inseries through two pairs of circuit-interrupting contacts, that is tosay through the units A and B, and the bridging bar 22. The operatingmechanism for the bridging bar 22 is arranged as is otherwise well knownin the art so that movement of said bar is co-ordinated with theapplication of air or gas pressure to the contact chambers 3 to provideisolation by disengagement of said bar from the contacts RIA and IBIB aspart of the circuit-opening operation either simultaneously with orafter the separation of the arc interrupting contacts I and 2 in each ofthe units A and B and extinction of the arc between said contactswhereby, upon removal of the air or gas pressure from said unit andconsequent reclosure of the arc interrupting contacts I and 2, thecircuit will remain interrupted by the bridging bar 22.

Figs. 3 and 4 show, also by way oi example,

another form of double-break switch in which, in place of the centralinsulating pillar 23 and bridging bar 22, the isolating movement abovereferred to is obtained by bodily movement of the arc interrupting unitswith respect to one another. For this purpose in the arrangement oi 3the contact chambers 3 are mounted on the pillars iii-A and IGB so thatthe insulating bushings fa extend toward one another and, in the closedposition of the switch, in line with one another, the insulating pillarsIGA and ICB are arranged` to be rotated in opposite directions to oneanother by suitable operating mechanism. The unit B is provided with aContact blade 3S carried by the plate Ib of that unit so as to inelectrical connection with the fixed contact l of said unit, whilst theunit A is provided with a co-operating jaw contact 3l carried by theplate lb ci the unit [i and thereby in contact with the ixed contact Iof the unit A. rThe two contact chambers 3 carry respective connectingmembers 533A and 52B mounted on the tops of the respective contactchambers 3 in a manner permitting relative rotational movement betweensaid members and contact chambers about the vertical axis or" theinsulating pillars IGA and ISB respectively. These membe s 32A and 32Bare connected with the two conductors 33 and 34,

The switch is illustrated in Figs. 3 and 4 in the circuit-closedposition. The isolating movement is obtained by the rotational movementof the insulating pillars IIIA and ISB and the switch units i?. B to thepositions indicated at A and B in Fig. 4, the isolating movement beingobtained by separation of the contacts 3D and 3|.

it will be understood that the desired isolating operation formaintaining the circuit open after reclosure of the arc-interruptingcontacts within the arcing chamber or chambers in singleand multi-breakswitches may be obtained by any other desired arrangement such as, forexample, by means of a separate air-break switch as is alsootherv-.f'ise well known in the art. One arrangement of this kindappears in Fig, 5, which shows, as will now be described, an alternativeapplication of arc-interrupting contact units according to Eig. l toprovide a multi-break switch.

In the arrangement shown in Fig. 5 two arcinterrupting contact units Aand B are mounted one above the other, the contact chamber 3 of the unitA being mounted on the upper end of the insulating pillar` I 0 as inFig. 1 whilst the Contact chamber 3 of the unit B is mounted upon andspaced with respect to the Contact chamber 3 of the unit A by means ofan insulating pillar du. rihe insulating bushings 4 of the two unitsextend in the same direction from the vertical axis of the insulatingpillars I0 and 40 and with their axes conveniently in the same verticalplane as is shown in the figure. The end plate Ib of the unit A isconnected by means of a conductor iii with the contact chamber 3 of theunit B whilst the member ib of said unit B is connected with theconductor 33. The Contact chamber 3 of the unit A is connected with theother conductor in general through contact means providing the isolatingmovement above referred t0. which isolating movement is provided in thearrangement shown by way of example in Fig. 5, by means of a separateisolating switch comprising a conducting blade 42 pivotally mounted atits right-hand end upon the upper end of an insulating pillar partiallyshown at 43 and engaging at its left-hand end with a contact member 44carried by the contact chamber 3 of the unit A. This conducting blade 42is adapted to be disengaged from the contact 44 by a clockwise movementto the position shown at 42 by operating means actuated through arotatable insulating pillar 45, such arrangements being otherwise wellknown in the art.

It Will be understood that further arc-interrupting contact units may bemounted above the unit B according to the number of breaks required forarc interruption in any particular application of the arrangementincluding those shown in Figs. 2, 3 and 4. One such modificationprovides a further unit C which is indicated in broken lines in Fig. 5,the additional unit C being supported on the unit B by a tubularinsulator 4D with the plate Ib of the unit B connected by conductor 4|with the contact chamber 3 of said unit C and the plate |b of said unitC connected with the conductor 33.

In another modification of the arrangement shown in Fig. the severalunits are mounted one above the other with the insulating bushings 4thereof extending in diametrically opposite directions to one anotherfrom the vertical axis of the arrangement, the conductor 4| extendingfrom the member Ib oi the unit A to the member 1 of the unit B and theconductor 4|', in the case of a three-unit switch, extending from themember |b of the unit B to the member 1 of the unit C.

It now will be appreciated that the above-described basic interruptingunit constructed in accordance with my invention as exemplified in Fig.1, which includes a metallic arcing chamber comprising a main bodyportion from which two cylinders or sleeves extend outwardly indifferent directions, one cylinder for receiving an easily removableinsulated contact element and the other for receiving an easilyremovable contact element which is electrically connected to the chamberbody, provides a very useful and desirable arrangement which is readilyadaptable for a variety of different applications; for it will beapparent that Whereas one connection of the circuit through the unitmust be made at the terminal Ib of the bushing 4, the other connectionmay be tapped off from any appropriate point at the metal casing 3 whichis most convenient for the particular application in View.

In the above-described examples, it will be clear that three suchconvenient optional tap-olf points from the chamber 3 were employed.There were, firstly, either the member 1 or I4 of Fig. 1 in the case ofthe arrangements illustrated by Fig. 2 and the unit A of Fig. 5;secondly, the cover 48 of Fig. l in the embodiment shown by Fig. 3; andthirdly, the clamping member 4a of Fig. 1 in the case of units B and Cdepicted in Figl 5.

Furthermore, the all-metal construction of the chamber 3 provides astrong fluid pressure confining casing in which the arc is drawn andblasted and which chamber moreover constitutes a mechanically strongrigid structure for mounting upon its hollow insulating pedestal andupon which may readily be stacked additional series interrupting unitsof similar configuration as clearly shown by Fig. 5. In all thesevarious embodiments, it will be observed that the breaking of the onejoint at flange |5 of cylinder 6 for the contact 2 is all that isnecessary in order to inspect the condition of the contacts or for theremoval of the retracting Contact element for repair cr replacement;moreover, these operations are possible without having to disturb anyline terminals in the process.

Reverting to Fig. 1, it will be seen that the upper Wall of the contactchamber 3 is provided with an opening 41 which as shown in Fig. 1 and inthe arrangements shown in Figs. 2, 3 and 4, is closed by a cover member48. In the application of the units of Fig. 1 to the arrangement shownin Fig. 5, or similarly for other arrangements of multi-break switch'comprising two or more units stacked one above the other, the coverplate 48 is omitted from the unit A so that the tubular insulatingpillar 4D will register with the opening 41 in said unit whereby the airor gas under pressure will also be delivered from the conduit |2 t0 theunit B and any further units mounted above the unit B, the insulatingbushings such as 40 housing, if desired, an insulating conduitcorresponding with that shown at |2 in Fig. 1. Th'e separation ofadjacent units in the same vertical column such as the separationprovided by the insulating pillars 40 and 40 may be graded so as toobtain uniform distribution of voltage between the several pairs ofarc-interrupting contacts.

Fig. 6 shows an arrangement comprising a plurality of arc-interruptingcontact units in accordance with Fig. 5 and incorporating a furtherfeature of the invention hereinbefore referred to whereby theseveralunits are maintained in the required position with respect to oneanother with the insulating pillars operating under compressive stressonly. Each of the contact chambers is provided on its lower externalface with a circumferential flange 50 surrounding the open ing at thisflange registering with a bore of the insulating pillar ||l in the caseof the unit A and with the bore of the insulating pillar 4|lin the caseof the unit B. The assembly of insulating pillars and contact chamberunits is shown mounted upon the upper wall, partially shown at 5|, of anair storage tank or other foundation member, said wall being providedwith an opening on which is seated a ring member 52 against which abutsthe lower end face of the pillar l0.

In the case of the unit A the cover member 43 (Fig. 1) is replaced by anannular space-r member 53 having a flange 54 seating on the upperexternal face of the contact chamber 3 of said unit, this spacer member53 registering within the opening 41 (Fig. 1) of said contact chamberand within the bore of the insulating pillar 40. The insulating tube |,2extends from the tank 5| th'rough the opening |I in the lower wall ofthe contact chamber 3 of the unit A, the spacer member 53, the openingIl in the lower wall of the contact chamber 3 of the unit B and throughthe opening 41 (Fig. 1) in the upper wall of the last-mentioned contactchamber, said insulating tube |2 being provided with openings at 55 and55 through which openings th'e pairs of contacts 2 of the two units Aand B respectively extend. At its lower end the tube |2 has securedthereto a metal sleeve 51 which registers Within the bore of the member52 and of the insulating pillar I0 and which is provided with a flange5B abutting against th'e end surface of the member 52. An air supplyconduit is partially shown at 59 making a flanged joint with the flan-ge58, this conduit being connected with a control valve whereby the airpressure within the tank 5| may be supplied to the tube |2. At its upperend the tube |2 has secured thereto a metal end closure member 60 whichregisters within the opening 41 in the unit B and is externallyscrew-threaded to receive a ring nut Gl abutting against the upperexternal face of the contact chamber 3 of said unit B.

It will be seen that tightening of the ring nut El against the upperface of the chamber 3 of the unit B will place the insulating tube l2 intension against the abutment of the flange 58 on the member whereby theinsulating pillars iii and i2 are placed in compression so that whereassaid outer insulating members IQ and iii may be fern ed of porcelain orother ceramic material not well adapted for operation in tension, theinternal pillar i2 may be formed of material having esirable propertiesfor operation in tension, for exampie said inner tube may be formed ofvulcanite or akelite paper. It will furthermore be seen that thearrangement is such that all the parts are retained in coaxial relationto one another by the flanges 50 and the members S, 5l and Si).

If desired capacitance or other grading means may be provided foredecting a uniform, or other desired gradn oi, distribution of potentialbetween the several pairs of (3o-operating contacts of the switch suchas to obtain a uniform distribution of potential between the severalbreaks and accordii to a further feature of the ine vention said meansare obtained by suitable proportioning of the capacitance of the tubularmembers bet veen the adjacent contact arrangements. For this purposesaid tubular members may be provided therein with layers of conductivematerial in the same manner as a, condenser bushing or the members maybe formed of a material having a suitably high specific inductivecapactiy such as, for example, the materia-l sold under the registeredtrade-mark. Rutile.

Fig. 7 shows a modified arrangement of two contact chamber unitsaccording to Fig. l to form a doublmbreak switch. In the arrangementshown in Fig. 7, the upper unit B instead of being mounted upon thelower member A. by means of an insulating pillar as in Fig. 5, ismounted directly thereon so as to be in electrical connection therewith.The insulating bushings 4 of the two units extends in diametrica-llyopposite directions from the Vertical axis of the arrangement theccductors 33 and 34 to be controlled by the sv ch are connected on theone hand with the member lb oi the unit B and on the other hand with thecorresponding member ib of the unit A. The unit A is shown by way ofexample as carrying on the plate 5b thereof a dried contactctn-operating with a pivoted blade fl? corresponding with thearrangement of isolator switch shown in Fig. 5.

The arrangement of the contact chambers 3 may be identical with thatshown in Fig. l except that the two units are connected together bymating franges and 8S formed respectively on the upper face or the unitA and the lower face of the unit B.

It will be appreciated that with the arrangement shown in Fig. '7additional units may be mounted above the unit B so as to be connectedin series therewith and furthermore, if desired, in place of the two ormore separate units, the several contact chambers may be formed integrail with one another by a single metal construction, that is to say ineiiect the insulating bushings @i and cylinders for all the units may bemounted in a common Contact chamber.

Fig. 8 shows a modication of the contact unit of Fig, l, and applicablein the various applications of the units as described with reference toFigs. 2 to '7 inclusive, in which, instead of the movable Contact 2being mounted in conductive relation with the arcing chamber, saidcontact 2 is insulated from id chamber. Thus, in Fig. 8 the movingContact 2 and piston 2a together with the resL ent annular contact 8 aremounted within a. member l0 which is received wn 1e ci second insulatingbushing ii le cylindrical portion i chamber S, replacing the cylinder oh that a-t 5 which, as shown in F locates the insulating bushing 4. Intment shown in Fig. 8 the cylindrical ier is provided with a portion i3of redt eter providing a flange against which the awnilar contact 8abuts to provide reaction corvicession spring 9 and pr riding e of thedischarge passage through larger than the cro contact 2 but somewhatsectional area or that Within said contact cylindrical bushing assembly78, "Fl is, oncentrically by means gainst 'the inner end of Gans of theend plate relation to the porst the outer end face of a the bushing 5having screw i in piace within the arcing chamber by The buslcylindrical portiev means oi anna.

the movable conremoved from the arcing chamber when on and replacementof the contacts required.

It will be understood i arrangements shown in the contacts the latter,or

y t if desired in the gs. l and 8 access to of or attention to a id tothe Contact I, may be ganeo oi' the bushing 4 from the arcing' chamberle Jushing is located in place by means removable annular retai lingring 51d secured to the contact chamber by or" ^own. In the case of lhowever, :ction or' and attention to the contact l h lie cylinder Eafter removal of the movi ing or the i bushing and the arcing chamber istl-e t where desired both may be provided with a n 2c described withrefnd working within copiston erence operating cylinders, by both thecontacts are ad pted to be displaced by the air or gas pressuiv to efec4the arc emt'nguishing contact separation. For e: nple, in thearrangements of both F 8, the contact l and bushing G may be arrangedsimilarly to the contact 2 and bushing li It will b einents according tothe inven'io nos further advantage, for nirreali switches, of redt cionly a coinparatively small "cribcd several embodigas 1elast interrupterunit c ntacts are arranged t 1ection substantially perpendicular to saluunits hoilow fluid conducting and si porting insulating to separate oustructure, which unit is economical. to manufacture, easy to assemble,readily accessible and adaptable for various practical applications; itshould be understood that my invention is not limited to specificdetails oi cons ructicn and arrangements herein illustrated, and thatchanges and modications may occur to one skilled in the art, withoutdeparting from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An electric circuit `breaker of the gas blast type comprising anarcing chamber formed of metal, a plurality of relatively movablecontacts associated with said chamber and arranged to draw an arc insaid chamber upon relative sellaration thereof, hollow insulatingstructure for supporting said arcing chamber, means for supplying gasunder pressure to said chamber for arc extinguishing purposes throughsaid hollow insulating structure, said metallic arcing chambercomprising a hollow body portion within which said contacts separate, anapertured base portion for said body adapted for mounting upon saidhollow insulating structure, a rst sleeve branching laterally koutwardfrom said body in one direction, a second sleeve branching laterallyoutward from said body in another direction, means disposed in said rstsleeve for supporting one oi? said contacts insulatingly with respect tosaid metallic arcing chamber, means cooperating with said second sleevefor supporting therein another of said contacts conductingly withrespect to said metallic arcing chamber, and a discharge opening fromsaid chamber for exhausting the gaseous products of said arc.

2. An electric circuit breaker oit the gas blast type comprising anarcing chamber formed of metal, a plurality of relatively movablecontacts associated with said chamber and arranged to draw an arc insaid chamber upon relative separation thereof, hollow insulatingstructure for supporting said arcing chamber, means for supplying gasunder pressure to said chamber for arc extinguishing purposes throughsaid hollow insulating structure, said metallic arcing chambercomprising a hollow body portion within which said contacts separate, anapertured base portion for said body adapted for mounting upon saidhollow insulating structure, a rst sleeve branching laterally outwardfrom said body in one direction, a second sleeve branching laterallyoutward from said body in another direction, means disposed in saidfirst sleeve for supporting one of said contacts insulatingly withrespect to said metallic arcing chamber, means cooperating with saidsecond sleeve for supporting therein another of said contactsconductingly with respect to said metallic arcing chamber, one of saidcontacts being hollow thereby deiining a discharge opening from saidchamber for exhausting the gaseous products of said arc.

3. An electric circuit breaker of the gas blast type comprising anarcing chamber formed of metal, a plurality of relatively movablecontacts associated with said chamber and arranged to draw an arc insaid chamber upon relative separation thereof, means including a pistonand a closing spring associated with one of said contacts to definetherewith a retractable contact, means for supplying gas under pressureto said chamber for causing relative separation of said contacts andextinguishment of the arc drawn therebetween, said metallic arcingchamber comprising a body portion within which said contacts separate,means for supporting one of said contacts insulatingly with respect tosaid body, a sleeve branching laterally outward from said body, meanscooperating with said sleeve for supporting therein said retractingcontact, a readily disconnectable joint for said sleeve the breaking 10of which suffices for the removal of said retractable contact, and adischarge opening from said chamber for exhausting the gaseous productsof said arc.

4. An electric circuit breaker of the fluid blast type comprising astructure defining an arc extinguishing chamber, a pair of relativelyseparable contacts arranged to draw an arc in said chamber, a fluidmotor for causing relative separation of said contacts, means forsupplying fluid under pressure to said chamber to operate said fluidmotor and to provide an arc extinguishing medium adjacent said contacts,said arc eX- tinguishing chamber comprising a hollow metallic bodyportion within which said contacts separate, an apertured base portionfor said body adapted for mounting on a hollow insulating supportingstructure through which said fluid is supplied, a sleeve extendinglaterally outward in. one direction from said body for supporting one ofsaid contacts and said fluid motor, an electric bushing extendinglaterally outward from said body in another direction for supporting theother said contact insulatingly with respect to said body, a readilydisconnectable joint for said sleeve the breaking thereof suflicing forthe removal of said iluid motor and providing direct access to saidcontacts, one of said contacts being hollow thereby deiining a dischargeopening from said chamber for exhausting the gaseous products of saidarc.

5. A multi-break electric circuit breaker comprising a plurality ofidentical arcing chambers eachhaving a pair of relatively movablecontacts associated therewith, each of said arcing chambers including ahollow metallic body within which said contacts separate to draw an arc,a iirst opening in one end of said body, a second opening in theopposite end of said body in axial alignment with said first opening,means associated with said rst opening to provide an interlocking maleportion for matching with said second opening, means for stacking saidarcing chambers one above the other in a column whereby adjacentchambers interlock together with all said openings in axial alignment sothat said chambers communicate with each other, means for supplyingiluid under pressure to one of said chambers and consequently to all ofsaid charnbers through said aligned openings, and means for causingrelative separation of all said pairs of relatively movable contacts inresponse to the supplying of fluid under pressure to said chambers.

6. A multi-break electric circuit breaker comprising a plurality ofidentical arcing chambers each having a pair of relatively movablecontacts associated therewith, each of said arcing chambers including ahollow metallic body within which said contacts separate to draw an arc,a rst opening in one end of said body, a second opening in the oppositeend of said body in axial alignment with said iirst opening, meansassociated with said first opening to provide an interlocking maleportion for matching with said sec- 0nd opening, means for stacking saidarcing chambers one above the other in a column including a tubularinsulator interposed between each adjacent pair of chambers, meansassociated with each said insulator to provide an interlocking maleportion at one end and a bore at the opposite end similar to the firstand second openings respectively in each said arcing chamber whereby allsaid stacked chambers and insulators interlock progressively with holesand bores in axial alignment, means for supplying iiuid under pressureto one of said chambers and consequently to all of said chambers throughsaid aligned openings, means for causing relative separation of all saidpairs of relatively movable contacts in response to the supplying offluid under pressure to said chambers, and means for connecting saidpairs of contacts in series relationship.

7. A multi-break electric circuit breaker comprising a plurality ofidentical arcing chambers each having a pair of relatively movablecontacts associated therewith, means for stacking said arcing chambersone above the other in a column, the adjacent walls of any two adjacentchambers being provided with aligned openings so that said chamberscommunicate with each other, a tubular member of insulating materialextending through said aligned openings from end to end of said column,means for supplying fluid under pressure to one of said chambers andconsequently to all of said chambers through said tubular member, andmeans for causing relative separation of all said pairs of relativelymovable contacts in response to the supplying of iluid under pressure tosaid chambers.

8. A multi-break electric circuit breaker comprising a plurality ofidentical arcinfJr chambers each having a pair of relatively movablecontacts associated therewith, means for stacking said arcing chambersone above the other in a column, the adjacent walls of any two adjacentchambers being provided with aligned openings so that said chamberscommunicate with each other, a tubular member of insulating materialextending through said aligned openings from end to end of said column,an insulating tube between each of said chambers, means for placing saidtubular member in tension and consequently said insulating tubes incompression, means for supplying iluid under pressure to one of saidchambers and consequently to all of said chambers through said tubularmember, and means for causing relative separation of all said pairs ofrelatively movable contacts in response to the supplying of fluid underpressure to said chambers.

9. A multi-break electric circuit breaker comprising a plurality ciidentical arcing chambers each having a pair of relatively movablecontacts associated therewith, means for stacking said arcing chambersone above the other in a column, the adjacent stalls of any two adjacentchambers being provided with aligned openings so that said chamberscommunicate with each otn a tubular member of insulating materialextending through s i aligned openings from end to end oi said columns,an insulating tube between each of said chambers, means for placing saidtubular memL in tension and consequently said insulating tubes incompression, means for supplying uid under pressure to one of chambersand consequently to all of said chambers through tubular member, meansfor cau ng relative separation of all said pairs of relatively movablecontacts in response to the supplying of fluid under pressure to saidchambers. and means for connecting said pairs of contacts in seriesrelation -p4 CEDRIC HAROLD if URSCHEIM.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 695,118 Read Mar. 1l, 19021,144,047 Merrian June 22, 1915 1,904,577 Uebermuth Apr. 18, 19332,255,198 Thommen Sept. 9, 1941 2,125,525 Thomien Aug. 2, 1938 2,253,196Paul Aug. 19, 1941 2,306,242 Bartlett Dec. 22, 1942

